1. Field
Embodiments relate to a compound for organic photoelectric device and an organic photoelectric device including the same.
2. Description of the Related Art
A photoelectric device is, in a broad sense, a device for transforming photo-energy to electrical energy, or conversely, for transforming electrical energy to photo-energy.
An organic photoelectric device may be classified as follows in accordance with its driving principles. A first organic photoelectric device is an electron device driven as follows: excitons are generated in an organic material layer by photons from an external light source, the excitons are separated into electrons and holes, and the electrons and holes are transferred to different electrodes as a current source (voltage source).
A second organic photoelectric device is an electron device driven as follows: a voltage or a current is applied to at least two electrodes to inject holes and/or electrons into an organic material semiconductor positioned at an interface of the electrodes, and the device is driven by the injected electrons and holes.
As examples, the organic photoelectric device includes an organic light emitting diode (OLED), an organic solar cell, an organic photo-conductor drum, an organic transistor, an organic memory device, etc. The organic photoelectric device may use a hole injecting or transporting material, an electron injecting or transporting material, or a light emitting material.
Particularly, the organic light emitting diode (OLED) has recently drawn attention due to an increase in demand for flat panel displays. In general, organic light emission refers to transformation of electrical energy to photo-energy.
The organic light emitting diode transforms electrical energy into light by applying a voltage or current to an organic light emitting material. The organic light emitting diode may have a functional organic material layer interposed between an anode and a cathode. The organic material layer may be formed as a multi-layer including different materials, e.g., a hole injection layer (HIL), a hole transport layer (HTL), an emission layer, an electron transport layer (ETL), and an electron injection layer (EIL), in order to improve efficiency and stability of the organic light emitting diode.
In an organic light emitting diode, when a voltage is applied between an anode and a cathode, holes from the anode and electrons from the cathode are injected to an organic material layer. The generated excitons generate light having certain wavelengths while shifting to a ground state.
An organic light emitting diode may include a low molecular aromatic diamine and aluminum complex as an emission layer-forming material. The organic layer may have a structure in which a thin film (hole transport layer (HTL)) of a diamine derivative and a thin film of tris(8-hydroxy-quinolate)aluminum (Alq3) are laminated.
A phosphorescent light emitting material may be used for a light emitting material of an organic light emitting diode in addition to a fluorescent light emitting material. The phosphorescent material may emit light by transitioning electrons from a ground state to an excited state, non-radiative transitioning of a singlet exciton to a triplet exciton through intersystem crossing, and transitioning the triplet exciton to a ground state to emit light.
In an organic light emitting diode, an organic material layer may include a light emitting material and a charge transport material, e.g., a hole injection material, a hole transport material, an electron transport material, an electron injection material, etc.
The light emitting material may be classified as blue, green, and red light emitting materials according to emitted colors, and yellow and orange light emitting materials to emit colors approaching natural colors.